In the applet below, a function [i]f [/i]is shown (black). You can enter in any function you like. [br]Its derivative function, f', is shown in gray. [br][br]As you move the slider, you will see a visual explanation of the relationship between the derivative and the gradient of the tangent for a value of x.[br][br]You can also move the tangent along the curve by moving the large white dot.